Prussia entered the ranks of the great powers shortly after becoming a kingdom, and exercised most influence in the 18th and 19th centuries. During the 18th century it had a major say in many international affairs under the reign of Frederick the Great. During the 19th century, Chancellor Otto von Bismarck united the German principalities into a "Lesser Germany", which excluded the Austrian Empire.

At the Congress of Vienna (1814–15), which redrew the map of Europe following Napoleon's defeat, Prussia acquired a large section of north western Germany, including the coal-rich Ruhr. The country then grew rapidly in influence economically and politically, and became the core of the North German Confederation in 1867, and then of the German Empire in 1871. The Kingdom of Prussia was now so large and so dominant in the new Germany that Junkers and other Prussian élites identified more and more as Germans and less as Prussians.